Differentiation between negative inotropic drugs by means of potentiated post-rest contractions in guinea-pig heart.
1. It was tested using isolated guinea-pig atria whether negative inotropic drugs could be differentiated by measuring force under both equilibrium conditions and after a rest period leading to potentiated beats. 2. A drug believed to interfere with sarcoplasmic reticular function, ryanodine, preferentially suppressed potentiated beats, whereas the calcium antagonists gallopamil and felodipine selectively depressed force under continuous stimulation. 3. Gentamicin and doxorubicin also exerted characteristic effects on the two force parameters, the former resembling calcium antagonists, the latter ryanodine. 4. The method used is suitable for a descriptive classification of negative inotropic drugs, possibly according to their cellular mode of action.
Herzig
S
S
Department of Pharmacology, University of Kiel, FRG.
Koch
A
A
Pfaffendorf
M
M
D000818:Animals; D004317:Doxorubicin / Q000494:pharmacology; D015736:Felodipine / Q000494:pharmacology*; D005260:Female; D005711:Gallopamil / Q000494:pharmacology*; D005839:Gentamicins / Q000494:pharmacology; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects*; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D012433:Ryanodine / Q000494:pharmacology*; D013997:Time Factors
D005839:Gentamicins; D012433:Ryanodine; D005711:Gallopamil; D004317:Doxorubicin; D015736:Felodipine